This invention generally relates to supplemental restraint systems. More particularly, this invention relates to a communication protocol for communicating information between sensors and controllers in supplemental restraint systems.
Supplemental restraint systems have recently gained increasing popularity in vehicles. The use of supplemental restraint devices such as air bags has been recognized as an advantage for preventing injury and preserving lives in the event of a vehicle crash. As technology has advanced, there have been additional proposals for additional supplemental restraint systems within vehicles. With the addition of each such device, additional communication is required between a controller and the device.
There have also been developments for including additional sensors on a vehicle for better detecting vehicle impact conditions. Moreover, with the increase of supplemental restraint devices, increased number of sensors are required for controlling each device. There is a need for effective communication between the various sensors or devices and the controller, which is responsible for deploying the supplemental restraint device as needed.
The need for communication between additional devices and sensors is coupled with the desire to maintain vehicle systems as simple, robust and economic as possible. Supplemental restraint systems, like most auxiliary systems incorporated into vehicles, must fit within space constraints and be cost effective.
This invention provides a communication protocol that facilitates communication between a single controller and multiple sensors or devices in a supplemental restraint system.
In general terms, this invention is a system for controlling a supplemental restraint device in a vehicle using a simple and robust yet versatile communication protocol between the various devices of the supplemental restraint system. The inventive arrangement includes a plurality of sensor devices supported at peripheral locations on the vehicle. A controller that communicates with the sensor devices interprets a series of pulses that each have a chosen duration to determine a condition sensed by the sensor devices based upon the duration and sequence of the pulses. Each sensor device preferably provides a unique series of pulses to be interpreted by the controller providing information regarding the unique condition sensed by each sensor.
The preferred arrangement includes a data portion within the controller, such as a look up table, that enables the controller to make a determination of the condition sensed by the sensor and to responsively control the supplemental restraint device as needed.
A method of this invention includes communicating between a peripheral sensor device and an electronic controller in a vehicle safety system. The method includes generating a plurality of pulses in a series responsive to a condition sensed by the sensor device. Each pulse has a chosen duration such that the sequence and durations of the pulses are indicative of the sensed condition. The combination of the order in which the pulses are received and their respective durations provides unique information regarding the condition detected by the sensor device. The condition sensed by the sensor device is determined by the electronic controller based upon the duration and sequence of the pulses. The electronic controller is then able to responsively control the operation of the supplemental restraint device needed.